Radio frequency (RF) receivers and transceivers can be found in numerous applications, particularly in the field of wireless communications and radar sensors. In the automotive sector, there is an increasing demand for radar sensors used in so-called “adaptive cruise control” (ACC) or “radar cruise control” systems. Such systems may be used to automatically adjust the speed of an automobile so as to maintain a safe distance from other automobiles ahead.
As in many applications, in which electronic circuits are used, energy consumption and heat dissipation may also be an issue for radar sensors, which are used for measuring distance and velocity of objects (so-called radar targets) present in the “field of view” of the radar sensor. Modern radar systems make use of highly integrated RF circuits (monolithic microwave integrated circuits, MMIC), which may incorporate all core functions of an RF font-end of a radar transceiver in one single package (single chip transceiver). Such RF front-ends usually include, inter alia, a voltage controlled oscillator (VCO), power amplifiers (PA), mixers, and analog-to-digital converters (ADC). As a result of the progress, which has been made in integrating RF circuitry, the problem of heat dissipation becomes even more preeminent. Another problem may result from cross-talk between radar sensors operating in close vicinity to each other (e.g. two automobiles driving side by side, each having a radar sensor).
There is a general need for radar sensors which have an improved (i.e. reduces) energy consumption and generate less heat during operation. Furthermore, a reduction of cross-talk may be desirable.